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[2620:137:e000::1:20]) by mx.google.com with ESMTP id w7-20020a639347000000b0046ec0715bd9si1909501pgm.818.2022.11.17.13.02.02; Thu, 17 Nov 2022 13:03:29 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b=k26wURFJ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229451AbiKQUqQ (ORCPT + 92 others); Thu, 17 Nov 2022 15:46:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232330AbiKQUqO (ORCPT ); Thu, 17 Nov 2022 15:46:14 -0500 Received: from mail-ed1-x52d.google.com (mail-ed1-x52d.google.com [IPv6:2a00:1450:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 64C1E6B202; Thu, 17 Nov 2022 12:46:13 -0800 (PST) Received: by mail-ed1-x52d.google.com with SMTP id v17so4311527edc.8; Thu, 17 Nov 2022 12:46:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :from:to:cc:subject:date:message-id:reply-to; bh=KgP3S5wtbBYj8SdinzbCrfNvgAs3PAFvpROmucDmbrA=; b=k26wURFJjpAGes5Qg4IUZqpMYdFUDn7hDKafR8BbKTEHRDYmdDQzgFxd9AHBDcnzKk O62ZCtW5/2bfj6z0aYF70pxnjN2sfoiLB2tz4VS3s1G7DuSdMO71YcH6f4w3H64x00aA OyMnYpEB4LQMTKdYfjl1Jr21JiyyJA0hMKj7Be+QnceuUhqVnWrh2X6ZZnrpXfPYyAhO rhj2b8YYDqNsjMRP1VNSnf4Vr4vdLsU6FbpwyuxNPgG9RPEUDlizbLIgGIYUE6ZPTNTR 6q0XEiCr0YmSd92Qbl8ncbAnY+GXkbFMtcm38XgoZnO9sCV7lXLno6zcFGtan7tJPjQ9 NL0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-disposition:mime-version:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=KgP3S5wtbBYj8SdinzbCrfNvgAs3PAFvpROmucDmbrA=; b=rdnZ7oBCVRuj4M0YAamoWXTt7dVIIPoCHacxTA6AG97k/ue4oWLCS4pGuc9LM7ryCb 0gw4VPXfSd/Rq0XJodLX7rCuOAHFgA1LocRmXGAlW7HIawrRInmAykR5L3yGSvEzm7oD wnVqRcObyx64BQRRlJ8s6+V1Q6bJzQVufBfNhecxC8AoFo2/YhJJvLw3xxinseNYFIU6 iIjJCSRnhwoJtysq7xFBJxhRakObS0412img3hU1Kwq20BCCD2ctngruqvFxabwwci0N eMWEFNFtsPI0TYJJLEpp6qYaQgHHGrjY3tBYuoUYfekpEUA3r2mE8a324Ny37Fe5il9X uzcQ== X-Gm-Message-State: ANoB5pl7rJRkXUg6QwhI3g04ZXLLgB43AjUhBrasXP5GVDusqN41Bcj1 O21Kp2wDvI5efSc3Wl4tk0aryXj0bQ== X-Received: by 2002:a05:6402:13d1:b0:469:4a1:96af with SMTP id a17-20020a05640213d100b0046904a196afmr799937edx.328.1668717971613; Thu, 17 Nov 2022 12:46:11 -0800 (PST) Received: from p183 ([46.53.253.26]) by smtp.gmail.com with ESMTPSA id v27-20020a17090606db00b0078175601630sm809209ejb.79.2022.11.17.12.46.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Nov 2022 12:46:11 -0800 (PST) Date: Thu, 17 Nov 2022 23:46:09 +0300 From: Alexey Dobriyan To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, jpoimboe@kernel.org, pbonzini@redhat.com, x86@kernel.org Subject: VMX HOST_RIP target alignment Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org One of the side effects of fixing retbleed for VMX was demoting HOST_RIP target from honorable function to a lowly label: -SYM_FUNC_START(vmx_vmexit) +SYM_INNER_LABEL(vmx_vmexit, SYM_L_GLOBAL) ffffffff81243c49: 0f 01 c2 vmlaunch ffffffff81243c4c: e9 a7 00 00 00 jmp ffffffff81243cf8 ffffffff81243c51 : ffffffff81243c51: 50 push rax Now I've never measured VM exit latency but is it important to align it at 16 bytes like Intel recommends for functions? vmalexey